Method of sealing boreholes and apparatus therefor



June 3, 1969 s. ULICZKY ETAL 3,447,605

METHOD OF SEALING BOREHOLES AND APPARATUS THEREFOR Filed Sept. 5. 1967 Sheet of 2 JNVENTORS ,4 rrys.

June 3, 1969 s. ULICZKY ETAL METHOD OF SEALING BOREHOLES AND APPARATUS THEREFOR Filed Sept. 5. 1967 'INVENTORS BY kn r JM United States Patent 0 3,447,605 METHOD OF SEALING BOREHOLES AND APPARATUS THEREFOR Sandor Uliczky and lstvan Zsoka, Budapest, Hungary, as-

signors to Mineralimpex Magyar Olaj-es Banyatermek Kulkereskedelmi Vallalat, Budapest, Hungary Filed Sept. 5, 1967, Ser. No. 665,360 Int. Cl. E21b 33/12 US. Cl. 166-187 4 Claims ABSTRACT OF THE DISCLOSURE A closing head for deep drill holes is surrounded by an expansible sleeve which is' inflated to close the drill hole. A release head has limitedmovement relative to the closing head and during upward movement breaks a frangible pipe to permit escape of the pressure within the sleeve, thereby to collapse the sleeve to permit removal of the closing head from the drill hole.

lt is known that the closing of mining drill-holes and pipe sections at a specific location is effected by means of a cement plug, by inserting a packer, or by means of some other closing device which is either breakable or removable with the aid of the drill-rod. All of these methods have certain disadvantages: for example, a placer tube is required for their insertion and this has to be assembled and dismantled. Inserting devices are also necessary e.g., drilling, stratum-testing, or probehandling equipment. Because of the time required for insetting and hardening the cement compound, for drilling through the cement, and for assembling and dismantling. cementing is an expensive solution, In order to be able to insert the packer, a placer-rod is required, and the assembly and dismantling of this also consumes much time and is therefore expensive.

The pierceable plugs. which are let down on a cable. are actually packers which are actuated by the tension of the cable after they have been fixed by means of explosives. by means of energy supplied by some other device above ground, or with a mechanical bond. Subsequent detachment of such plug is impossible; they are removed by means of the drill-rod.

As regards material, time and labour required. these methods and the equipment needed for their execution are very exacting; moreover they are of very complex construction. Because of these disadvantages. attempts have recently been made to provide new solutions; for instance, hollow cylindrical plugs have been let down into the drill-hole, the said plugs being filled with explosives; the explosive was detonated, thus deforming the plug and causing it to jam in the drill-hole or pipe cross section, and thus to produce a closure. In most cases. however. the drill-hole and the pipe-lining are also damaged by the blast. Because of this disadvantage, especially in view of the damage caused, use was made in another manner of a plug made of a resilient material, the said plug being pressed into the cylindrical cavity of the device let down into the drill-hole. Here again. explosives were used. the drill-hole being closed off by the shootingout of this plug. However. these devices for obtaining a closure by means of a closure plug shot out with explosives have not proved to be satisfactory, partly because the precise location of the shot out plug cannot be determined in advance, but partly because removal of such plugs is possible only with the aid of a drill-rod. i.e. by drilling; furthermore. the handling of such devices filled with explosives is dangerous.

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With the more modern known devices for closing drillholes. use was made of a hose connected to a. pump, both of which were let down into the drill-hole. After the pump, actuated in the drill-hole, had filled the hose to a suitable pressure with the liquid in the drill-hole, the pump was released from the device.

This is a complex device consisting of many components, since two electric motors, a pump, a tubular body as a carrier, a valve system and the electrical current supply parts are needed for its operation. Moreover. operation of this device is unreliable, since the sludge and the sand-containing water in the drill-hole make it impossible to reconnect the hose to the pipe. Thus the closing hose cannot be detached, but must be eliminated by drilling with the drill-rod. Furthermore, by reason of,

the sludge and sand in the flushing liquid, the valve in the filled hose cannot be permanently closed and sealed, and the closure therefore loses its etfectiveness in a short time.

The method according to the invention and the apparatus associated therewith provide a new solution which is free of all of the disadvantages of the various designs enumerated and tested up to now, and which furthermore is of very simple and reliable construction.

The essence of the method and of the apparatus associated therewith. according to the invention, consists in that the closure to be effected at a given depth in the drill-hole or pipe section is effected mainly by using local hydrostatic energy or, if this is lacking. by using energy brought in from above ground and stored in the container of the closing unit, e.g. compressed, gas from a gas bottle or a medium (e.g. chemicals) suitable for producing energy. i.e. by the energy then developed in situ. The unit is let down by means of a rope or cable; the closure is free from leaks; detachment and removal of the unit is effected by means of its own detaching device by actuating the rope.

The method. and the apparatus foi' its execution is explained with the aid of two drawings illustrating examples of execution. wherein:

FIGURE 1 is a section of the device actuated by local hydrostatic energy;

FIGURE 2 shows. also in section, the unit being acmated by the energy stored in the closing unit.

The embodiment according to FIGURE 1, and the operation thereof, is more advantageous than all methods and devices hitherto used for similar purposes, since the insertion and placing of the unit in the drill-hole is effected by means of a rope, and there is thus no need to use the drill-rod or a placer pipe; there is no assembly or dismantling and the resulting costs are therefore saved. As a result of the automatic control provided in the embodiment of FIGURE 1, no actuating energy from above ground is required to actuate the unit. It will follow that the use of the unit and the method is quicker and cheaper than any existing method.

The closing unit, assembled above ground in accordance with assembly instructions, is let down into the drill pipe or drill-hole l. to the required depth, by means of the cable or a line containing a current-carrying wire 2. When the required depth is reached, starting valve 3 is set at open." e.g. by means of an electric pulse through a relay. or by heating with geothermal heating, or by a clock mechanism. or by chemical or other means. As a result of this, the liquid in drill-hole 4 flows through open valve 5 into the space above piston 7 which moves in the larger-diameter operating cylinder of cylindrical body 6 consisting of two operating chambers. The force corresponding to the piston area and pressure'thus forces the piston downwards. This pressure-force is transferred by piston rod 8 to piston 9 moving in the smaller-diameter cylinder, where the pressure-force is transferred to the liquid fillingcylinder 10. This liquid is thus exposed to an excess pressure corresponding to the ratio of the two piston areas. Piston 9, which exerts pressure amplified by the hydrotransformer described, forces the liquid out of chamber 10, through pressure pipe 11, non-return valve 12 and channel 13, into liquid chamber 14, pressing clos ing casing 15, which surrounds this space like a cylindrical casing, against wall 1 of the lining pipe. Closing casing 15 surrounds closing-head body 16 like a cylindrical casing, and adapts itselfbent by its own resilient tension to the recesses at the top and bottom of the cut-out provided for clamping closing casing 15. The said closing casing can expand only outwardly, since the shape of the closing head both at 16 and at the top, at 16a, holds it clamped and restricts or prevents any movement in any other direction. The closing head, consisting of parts 15, 16 and 16a, connected to end-plate 6b of cylindrical body 6 by resiliently-connected distance rods 17. In liquid space 14, the pressure rises to a value resulting from the area ratio of pistons 7 and 9 and from the pressure of the liquid in space 4, and then remains constant at this value. When this closing pressure is reached, it presses casing 15 against lining pipe 15, so that the sections of the said lining pipe above and below the device are separated from raised by means of cable 2, the pull causing distance rods 17 to be released from the spring connection 18. Further pulling breaks pressure pipe 11. Any outflow of liquid is prevented by non-return valve 12, and the bottom part, the so-called closing head of the unit, remains firmly in position in the lining pipe. Thereafter, the top part of the unit, consisting of the pressure amplifier and hydrotransformer with. cylinder 6, can be dismantled or withdrawn by means of cable (rope 2). The necessary deposit tests and production work may now be carried out.

Release of the closing device, after the necessary work has been carried out, is effected by means of a pair of wedge-tongs or releasing device, designed for the purpose and let down on rope 2. The said pair of wedge tongs grips release head 19 and then, when the rope is pulled, tears away, by means of flange 19a, release pipe 20, which is sized to shear by means of shear pin 21. As a result of this, the excess pressure obtaining in liquid chamber 14 blows out into the drill-hole and equalizes the pressure above release pipe 20. But the closing action now ceases.

. Flange 19astrikes the heads of bolts 22, fitted to the locking housing, and carries them along, and the closing head can be withdrawn from the drill-hole on the rope.

After readjusting pistons 7 and 9 and replacing pressure pipe 11, theclosing unit may be re-used. The spring connection may also be a connection assembled with bolt heads 22 and capable of being released by a pull; moreover, pressure pipe 11, instead of being made to break away, may also be made in the form of a detachable connection. Upper part 16a of closing head 16 may also be made in the form of a screw-on workpiece, which is of advantage in assembling or exchanging closing casing 15.

The embodiment of the closing-unit explained above is only one of many possibilities. Thus, for instance the hydrostatic energy mentioned in the description may also be used as pressure energy, or the unit may also be actuated by means of an energy-storing bottle connected thereto and to a larger-diameter cylinder 6a in the unit, to piston 7, and to starting valve 3, the pressure acting upon piston 7 be supplied from the energy stored in the gas bottle.

The device is started by means of starting valve 3. This valve may be of various designs: e.g. a fusible metal heated with electric heater-coil 23, or a valve opened by clockwork, or a mechanically perforatable closing element; other solutions, either time-adjusted or operated above ground are also possible.

There are also several means of ensuring actuating energy, for example: hydrostatic energy, geothermal energy, energy released by chemical processes (e.g. gasification, evaporation, etc.)

An embodiment of this kind is illustrated in FIGURE 2, in discussing which the reference numerals and terms used are'the same as in FIGURE 1 for identical parts.

The closing unit may be let down by means of the tong suspension attached to release head 19, or by means of two ropes or cable passing eyes 24. The gas which fills space 14 in closing casing 15, and exerts pressure on casing 15, is charged into energy-storage chamber 25 of closing-head body 16. The closingunit is then let down to the desired depth. The gas exerting the pressure-force may pass through pipe 26 from energy storer (accumulator) 25 into space 14 in the expanding closing casing 15, when current is supplied through cable 2a to heatercoil 23. By melting metal insert 27, this opens the connection between chamber 25 and pipe 26. The compressed gas then passes through pipe 26 into space 14, where the expansion pressure presses closing casing 15 against wall 1 of the lining pipe. After the closing unit has been located, the two ropes are released by pulling them through eyes 24; cable 2a and the power connection to coil 23 also pulls away.

In order to release the closure and withdraw the unit from the drill-hole, the gripping head adapted for connection to conical head 19 is let down on the placer rope. The connection having been made, the placer rope is raised whereby conical suspension head 19, together with its baseplate 19a, is raised to the heads of guide bolts :22. Shear pin 28 passes transversely through the shaft of the saidconical head. During lifting, this exerts a tensile force on the cross section of release pipe 29 in the closing device, and tears it away. As a result of this, the gas pressure can pass into the drill-hole through pipe 26 and under baseplate 19a of conical head 19, out of theunit. This causes the pressure obtaining in the interior of the unit to be equalized with the surrounding pressure, and the section-closing mechanism of the device is eliminated. If conical head 19 is now moved further in an upward direction, baseplate 19a engages with bolt heads 22, carries the device along, .thus enabling it to be pulled out of the drill hole. Chamber 14 may be filled and, if necessary, emptied via non-return valve 30.

Since technical mishaps, water damage, and other external factors must be allowed for, erg. with the lining pipe pressed in, when it is necessary to remove the closing head of the device, it is preferable to make the said head of an easily destructible material, or an alloy thereof, e.g. aluminum or malleable cast iron.

By repeating the process described, namely refilling the hydrotransformer or energy-storage space, and by carrying out the operating cycles, the closing device may be re-utilized as often as may be desired.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a device for closing deep drill holes comprising a closing head, suspension means for lowering the closing head into a drill hole, the closing head having an expansible casing, means for inflating the expansible casing with a pressure medium, and a release head by which the closing head is lifted out of the drill hole; the .improvement comprising a frangible release pipe communieating between the inside of the expansible casing and the outside of the closing head, and means responsive to upward movement of the release head to break said release pipe to permit escape of the pressure medium and collapse of the expansible casing.

2. A device as claimed in claim 1, and means mounting said release head on said closing head for limited vertical movement of said release head relative to said closing head, and stop means for stopping vertical movement of said release head relative to said closing head after said pipe has been broken.

3. A device as claimed in claim 2, said pipe having an enlargement thereon engageable with said release head upon upward movement of said release head relative to said closing head for breaking said pipe upon continued upward movement of said release head after contact with said enlargement.

4. A device as claimed in claim 1, there being an inlet for pressure medium into said expansible casing, and a differential piston having a pair of piston heads of different areas, the piston head of smaller area communicating with said inlet and the piston head of larger area being adapted to communicate with the drill hole outside said closing head.

References Cited UNITED STATES PATENTS Boer et a1 166187 Huber 166-187 X Huber 166-187 X True et a1 166-187 X Evans 166-187 X McCulloch et a]. 166187 X Peppers 1 66-487 X Brown 166-187 X JAMES A. LEPPINK, Primary Examiner. 

